1. Field of the Invention
The present invention relates to a slot machine which includes a plurality of video reel strips.
2. Description of the Background Art
Conventionally, as a slot machine including a plurality of video reel strips, for example, there is a model which has the below-mentioned technology. In the technology which such a model has, since a game is subsequently initiated by the occurrence of triggering, the plurality of video reel strips are upgraded. When the plurality of video reel strips are upgraded, it becomes easy for a player to obtain a winning combination (for example, refer to US patent application publication 2012/0172106).
However, as a method of upgrading the plurality of video reel strips, for example, a method in which the number of wild symbols which can be substituted with any symbols is increased is adopted. Then, since it is easy for a player to recognize the increase in the number of the wild symbols, a player can soon perceive that the plurality of video reel strips have been upgraded.
Accordingly, a new design for upgrading the plurality of video reel strips has been desired by players.
Therefore, in view of the above-described respect, the present invention was made. An object of the present invention is to provide a slot machine which realizes a new design for upgrading the plurality of video reel strips.
In addition, there also is a slot machine equipped with a jackpot function. The jackpot function serves such that each predetermined money amount is accumulated each time betting is conducted and when a jackpot is won, a money amount based on the money amounts accumulated until then is paid out to a player. In the conventional slot machine, money amounts to be accumulated can be determined in accordance with the number of bets placed when betting is conducted, and when the number of bets placed is large, the accumulated money amounts is large whereas the number of bets placed is small, the accumulated money amounts is small.
Therefore, a player who expects winning of a jackpot increases the number of BETs and proceeds with a game. Accordingly, while such a player is playing the game, upon the occurrence of the winning of the jackpot, a benefit in accordance with the investment made by the player can be provided.
However, while such a player is playing the game, without the occurrence of the jackpot, any benefit cannot be provided despite the investment made by the player. Furthermore, another player starting a game thereafter may to be provided with a benefit awarded by the jackpot. Therefore, unfairness results between a player who has made an investment and a player who has not made an investment. This leads to an increase in the number of players who each decreases the number of BETs placed to proceed with a game, and as a result, the consumption of coins is decreased, resulting in a likelihood of a decrease in a profit of a shop such as a casino.
Given this situation, a slot machine which can reduce the unfairness among players and allows a player to proceed with a game in expectation of a jackpot has been desired.